`local` - create a function-local variable

local [-i] NAME[=VALUE]...

Options you will use

-a: The variable is an indexed array.
-A: The variable is an associative array (keys are strings).
-i: The variable is an integer: assignments are evaluated as arithmetic.
-n: A nameref: the variable is another name for the variable named in its value.
-r: Read-only.

Gotchas

local x=$(cmd) swallows cmd's exit status, because the status you get is local's. Split it: local x; x=$(cmd). shellcheck SC2155.

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